Calling replace in archetype xml leads to path error

I have artifact ids under the form "a-b-c" and I'd like for my archetype to have a package like "a.b.c". So, I do the following:

<archetype-descriptor
xsi:schemaLocation="http://maven.apache.org/plugins/maven-archetype-plugin/archetype-descriptor/1.0.0 http://maven.apache.org/xsd/archetype-descriptor-1.0.0.xsd"
name="bmed-sb-archetype"
xmlns="http://maven.apache.org/plugins/maven-archetype-plugin/archetype-descriptor/1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<requiredProperties>
    <requiredProperty key="package">
        <defaultValue>${StringUtils.replace(artifactId,"-","")}</defaultValue>
    </requiredProperty>
 <fileSets>
    <fileSet filtered="true" packaged="true" encoding="UTF-8">
        <directory>src/main/java</directory>
        <includes>
            <include>**/*.java</include>
        </includes>
    </fileSet>

But doing so will give me:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-archetype-plugin:3.1.2:generate (default-cli) on project standalone-pom: java.io.IOException: The filename, directory name, or volume label syntax is incorrect

If I remove that replace everything works fine. Why?